Damage? Whether its a hammer, lighting bolt, a dark curse or a large bicep, gather up all your D6s. Even the ones in all your board games. Roll the whole set twice (or just multiply by 2).

What can hit em? Spells possibly, and +5 weapons.

What happens if the God actually get's killed? There's a slim chance, but maybe they are sent into the underworld, maybe they recreate themselves in space and rule another planet, maybe they are reincarnated into a far eviler terrible version of themselves? Who knows.